[SOLVED] Do Holes move in Semiconductor Materials?

[tahir4awan]

There is a confusion which I am not able solve due to different point of views. What I have learned from electronics books that holes in semiconductor do not move. It is an imagination or illusion created by electrons because when electron moves from valence band to conduction band it leaves a hole behind it. But suddenly another electron falls into it from conduction band to valence band and the process keeps on.

I have seen this video which again created confusion
p-n-Juction-And-Diodes - YouTube

In this video, it is shown that in P type material electrons are immobile ion while holes are mobile and in N type material holes are immobile while electrons are mobile.

Also in some books it is said that positive terminal of battery attracts electrons and negative terminal of battery attracts holes. The question arise here when holes are immobile then how can a negative terminal of battery attracts them?

I know most of people say that in forward biasing of a diode negative terminal of battery pushes electrons to P type and these electrons falls into valence band and move to positive terminal as valence electrons. But their theory fail in reverse biased because again same question arise that what negative terminal of battery attracts?

My question is simple can anybody tell me what really happened in semiconductor materials in forward and reverse biased condition?

 

[DartPlayer170]

Did you ever have one of those puzzles made of a bunch of little squares with one hole? You had to solve the puzzle by moving the squares around. The hole was there to allow you to move the squares into it.
Was the hole moving?

 

[errakeshpillai]

Really Nice pointing Example @DartPlayer170.

The holes don't move.
Its the electron that occupy a hole and leave a vacant hole behind them.
So it seems that electron moved towards the positive terminal and the hole moving towards the negative terminal.

The negative terminal attracting holes is in the sense that it will repel the electrons creating holes in the region nearer ti it.

 

[permute]

However, it is useful to model the system as a particle (hole) that moves. After all, even in semiconductors you are at a macro-level in terms of electrons -- trillions of electrons moving in/out of their valance band. You're really never even talking about specific electrons or holes, but rather statistics. After all, with any current, the specific electrons that flow from one terminal might not reach the other terminal. There isn't any charge accumulation, so statistically the same number of electrons flow into/out of the terminals.

But it is nicer to keep this view and think of both electrons and holes as flowing particles.